As a drive unit for recording digital data to a magnetic tape and reproducing digital data recorded on the magnetic tape, a so-called tape streamer drive is known. The tape streamer drive of this type enables recording of a large quantity of digital data, for example, approximately several ten to several hundred gigabytes, depending on the tape length of a magnetic tape housed in a tape cassette as a medium. Therefore, this tape streamer drive is broadly used for applications such as backup of data recorded on a medium such as a hard disk of a computer body. Moreover, this tape steamer drive is preferably used in saving image data or the like having a large data size.
As a tape streamer drive as described above, for example, there has been proposed a tape streamer drive adapted for carrying out recording and/or reproduction of data using an 8-mm VTR tape cassette as a recording medium and a helical scan system with a rotary head.
In the tape cassette having a magnetic tape housed therein, which is used for the tape streamer drive of this type, since only the tape medium is a medium for recording data, various data such as data for management and data for system setting are also recorded on the tape, other than main data as a storage object.
In practical applications, a user often wants to read the data in the tape cassette when the tape cassette is not loaded. For example, in a library device having a cassette replacement function such that many tape cassettes are housed in a magazine form and selectively supplied to a tape streamer drive, it is preferred that certain data can be read from an outer casing of the cassette in order to identify the tape cassette to be carried. Therefore, it is considered, for example, to paste a bar code label on the cassette casing so that the library device or the like reads the bar code label using an optical reader or the like, thus enabling discrimination of information for identification, for example, the tape cassette number.
The bar code pasted on the cassette casing is not rewritable and have a small quantity of information. Therefore, it is not suitable for a system which carries out relatively advanced processing.
Meanwhile, for the above-described tape streamer system, a tape cassette having a non-volatile memory housed within a cassette casing is developed. This is adapted for recording management information about recording or reproduction of data to or from a magnetic tape, manufacture information and use history information of the tape cassette and the like, into the non-volatile memory. By doing so, the operating efficiency is much more improved than in the case of recording these management information and the like onto the magnetic tape. Specifically, these management information and the like need to be read and confirmed every time recording/reproduction on the magnetic tape is carried out, and these management information and the like need to be updated after the recording/reproducing operation. If the management information and the like have been recorded at a specific position on the magnetic tape, for example, at the leading end of the magnetic tape, the tape must be wound to the specific position before and after each recording/reproducing operation. This also regulates the position on the tape for carrying out tape loading and unloading operations. However, such inconvenience is eliminated by recording the management information and the like into the non-volatile memory.
The non-volatile memory is accessed by providing a connector terminal which is supported by the tape streamer drive.
Recently, there has been developed a structure such that an antenna and a radio communication circuit are arranged in a tape cassette together with a non-volatile memory and the non-volatile memory is accessed in a non-contact state. That is, a radio communication circuit is arranged in the tape streamer drive or the like and recording/reproduction of data to/from the non-volatile memory can be carried out in a non-contact state to the tape cassette.
In the case of a tape cassette having a non-volatile memory of such a non-contact interface system, it is conceivable to carry out data reading which would be carried out with a bar code, by using the non-volatile memory. For example, when the library device selects a specific tape cassette from a magazine in which many tape cassette are housed, data proper to each tape cassette may be read through radio communication. However, it is practically difficult since radio interference easily occurs from the neighboring tape cassettes because of the radio communication. More advanced processing, such as, an operation for the library device to write management information, is difficult to realize. Particularly, in order to carry out appropriate data writing or reading while preventing radio interference, it is necessary to securely authenticate a tape cassette of a communication partner or a non-volatile memory within the tape cassette and to carry out various communications for actual control after the authentication. Moreover, it is demanded to reduce the quantity of data to be transferred in various communications to the minimum level.